A novel reactive power overexcitation regulation technology for synchronous generator, comprises measuring a stator voltage, a stator current, an active power and a reactive power of the synchronous generator; calculating the allowable upper limit value of the reactive power of the generator according to the allowable stator current of stator heating, and calculating the allowable value of the reactive power of the minimum stator current of the generator according to the contact reactance between the generator and the grid; comparing the stator current with its allowable value, calculate the excess calorific value of the stator of the generator if the calculated actual stator current is larger than its allowable value, enter reactive power overexcitation limiting regulation mode if the excess calorific value of the generator reaches the upper limit of the allowable heating margin of the generator; and using the larger value between the allowable upper limit value of the reactive power and the allowable value of the reactive power as the goal value of the reactive power regulation to maintain the output reactive power of the generator equal to the goal value. The present invention can protect the safety of the generator, and is beneficial to support the grid voltage to improve the stability of the power system performance.
Legal claims defining the scope of protection, as filed with the USPTO.
1. A novel reactive power overexcitation regulation technology for synchronous generator, wherein, comprising: measuring a stator voltage, a stator current, an active power and a reactive power of the synchronous generator; calculating the allowable upper limit value of the reactive power of the generator according to the allowable stator current of stator heating of the generator, and calculating the allowable value of the reactive power of the minimum stator current of the generator according to the contact reactance between the generator and the grid; comparing the calculated actual stator current with its allowable value, calculate the excess calorific value of the stator of the generator if the calculated actual stator current is larger than its allowable value, enter reactive power overexcitation limiting regulation mode if the excess calorific value of the generator reaches the upper limit of the allowable heating margin of the generator; using the larger value between the allowable upper limit value of the reactive power and the allowable value of the reactive power of the minimum stator current as the goal value of the reactive power regulation to maintain the output reactive power of the generator equal to the goal value.
2. The novel reactive power overexcitation regulation technology for synchronous generator according to claim 1 , wherein the goal value of the reactive power regulation is calculated as: { Q G 1 ( U t , P e ) = U t 2 i t lim 2 - P e 2 Q G 2 ( U t , P e ) = U t 2 2 X E U t 4 4 X E 2 - P e 2 Q G ( U t , P e ) = max { Q G 1 ( U t , P e ) , Q G 2 ( U t , P e ) } wherein, item is an allowable value of the stator current, X E is a contact reactance between the generator and the grid, P e is an active power, U t is a stator voltage, Q G1 is an allowable upper limit value of the reactive power calculated according to the allowable stator heating, Q G2 is an allowable value of the reactive power calculated according to the minimum stator current, and Q G is a goal value of the reactive power overexcitation regulation.
3. The novel reactive power overexcitation regulation technology for synchronous generator according to claim 2 , wherein the startup logic is calculated as: { i t 2 = P e 2 + Q t 2 U t 2 i t > i tth C t = ∫ ( i t 2 - i tn 2 ) dt C t > C a wherein, i tn is a stator current rating, i tth is a start threshold of stator heating calculation, C t is a calculated value of stator heat capacity, C a is an allowable pre-setting value of stator heating, P e is an active power, U t is a stator voltage, and I t is a stator current.
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April 23, 2018
January 14, 2020
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